Man

A man's worst difficulties begin when he is able to do as he likes.
T. H. Huxley

The man in black fled across the desert, and the gunslinger followed.

Think of a sick man in such a place as Saint Martin's Court, listening to the footsteps, and in the midst of pain and weariness obliged, despite himself (as though it were a task he must perform) to detect the child's step from the man's, the slipshod beggar from the booted exquisite, the lounging from the busy, the dull heel of the sauntering outcast from the quick tread of an expectant pleasure-seeker--think of the hum and noise always being present to his sense, and of the stream of life that will not stop, pouring on, on, on, through all his restless dreams, as if he were condemned to lie, dead but conscious, in a noisy churchyard, and had no hope of rest for centuries to come.

Man is a biped, but fifty men are not a centipede.

Chesterton

The greatest nuisance to mankind is man.

Samuel Butler

Man is nature's sole mistake.

W. S. Gilbert

Each human being is a more complex structure than any social system to which he belongs.

A. N. Whitehead

From such crooked wood as that which man is made of, nothing straight can be fashioned.
Kant

The only proof that man is the noblest of all creatures
is that no other creature has ever denied it.